Block C – Vehicle Preparation

Trends

There is an increased use of alternate substrate materials such as plastics, metal alloys and composite panels. These new materials affect the preparation and refinishing processes.

Products being introduced include low VOC solvents, interface pads, faster-drying materials and flexible foam-backed sandpaper. Existing products such as water-borne primers, ceramic topcoats and solvent impermeable putties are increasingly being used.

Related Components

All components apply.

Tools and Equipment

See Appendix A.

Task 5 Prepares surface.

Context

Automotive painters must prepare substrates and existing surfaces for the application of undercoats and topcoats. Using proper tools, materials and techniques are important to achieve a smooth transition from repaired area to existing finish.

Required Knowledge

• K 1 types of cleaners such as soapy water, degreasers and pre-cleaners
• K 2 cleaning techniques
• K 3 types of contaminants such as road tar, tree sap and silicone
• K 4 types of trim and accessories and their method of attachment
• K 5 composition of trim and accessories such as plastic, glass and metal
• K 6 types of fasteners for exterior and interior trim
• K 7 effect of temperature on removal of components
• K 8 substrates such as metals, plastics and composites
• K 9 types of imperfections such as minor dents, rock chips and scratches
• K 10 repair techniques such as feather edging and stripping
• K 11 types of masking materials such as paper, tape, foam, plastic sheeting and spray mask
• K 12 masking procedures
• K 13 stripping methods such as chemical, mechanical and media blasting
• K 14 effect of chemical stripping, mechanical stripping and media blasting on substrates
• K 15 types of media blasting such as glass, sand, soda, plastic beads and walnuts
• K 16 PPE and safety equipment requirements
• K 17 types of abrasives and their characteristics, effectiveness and limitations
• K 18 sanding methods such as wet and dry
• K 19 sanding techniques such as block, scratch pad, back and final sanding
• K 20 sanding materials such as scratch pads, sandpaper and blend paste (blend prep)
• K 21 adhesion capability of materials to be applied
• K 22 purpose of the guide coat

Sub-task - C-5.01 Performs initial preparation.

Key Competencies

• C-5.01.01 remove trim and accessories to ensure thorough sanding of inaccessible areas
• C-5.01.02 handle and store trim and accessories according to best practices to prevent damages or loss
• C-5.01.03 remove dust, loose debris and moisture from area to be prepared and painted to ensure a clean finish free of surface imperfections
• C-5.01.04 remove residual two-way tape or decal glue using tools and products such as heat guns/lamps, eraser wheels and solvents
• C-5.01.05 apply appropriate cleaner based on substrate and refinish material to be applied, using the wipe-on wipe-off method, to improve adhesion and for safety purposes (i.e., avoiding static charged flash fires)

Sub-task - C-5.02 Masks vehicle.

Key Competencies

• C-5.02.01 apply masking tape to avoid over and under masking
• C-5.02.02 apply spray mask (liquid mask) using appropriate equipment to protect areas not to be refinished
• C-5.02.03 apply masking tape to the edges of adjacent panels and trim/mouldings using masking techniques to protect against damage during preparation
• C-5.02.04 use plastic sheeting to cover vehicle and secure edges according to manufacturers’ recommendations to protect against overspray
• C-5.02.05 use vinyl tape to prevent bridging paint or to make hard edges based on task at hand
• C-5.02.06 use edging tape behind moulding to prevent problems such as bridging, peeling and overspray
• C-5.02.07 apply masking tape and paper using methods such as back masking and reverse masking to avoid hard edges
• C-5.02.08 install soft edge tape to inner panels to protect against overspray and to leave a soft edge

Sub-task - C-5.03 Strips surface.

Key Competencies

• C-5.03.01 apply chemical stripper to work area according to manufacturers’ recommendations
• C-5.03.02 neutralize chemical residue according to manufacturers’ recommendations
• C-5.03.03 mechanically strip work area using tools such as dual action sanders or grinders, for task at hand and according to best practices
• C-5.03.04 media blast work area using appropriate media according to substrate
• C-5.03.05 remove dust residue from work area after mechanical or media stripping according to best practices

Sub-task - C-5.04 Sands surface.

Key Competencies

• C-5.04.01 prepare blend area by wet or dry sanding or using scratch pads and blend paste (blend prep) to achieve a uniform colour match, according to manufacturers’ specifications
• C-5.04.02 featheredge repaired area by dry sanding using P180-P320 grit sandpaper to achieve a smooth transition from repaired area to existing finish
• C-5.04.03 back sand using P320-P600 grit to prepare for the application of undercoats
• C-5.04.04 remove excess primer surfacer, putty and filler material by block sanding using the cross hatch method to achieve a level surface

Task 6 Uses repair materials.

Context

Repair materials include putties, primers, primer surfacers, gravel guards and seam sealers. The proper use and application of these products is important to set the foundation for the refinishing process.

Required Knowledge

• K 1 types of putties such as polyester and glazing putties
• K 2 types of substrates such as plastic, composites and metals
• K 3 product mixing and application techniques
• K 4 selection of putties to maintain characteristics of existing substrate (i.e., flexibility of bumper covers)
• K 5 role of environmental conditions on working and curing times
• K 6 limitation of use of putties
• K 7 types of primers such as etch and epoxy
• K 8 types of primer surfacers such as two-part, tintable and UV cure
• K 9 application techniques such as spray-on, roll-on, spreadable and aerosol
• K 10 types of adhesion promoters
• K 11 limitations of primers and primer surfacers
• K 12 flash-off times, cure times, induction times and pot life
• K 13 use of guide coat
• K 14 sandpaper grit
• K 15 uses of sanding paste
• K 16 sanding methods such as wet and dry
• K 17 sanding techniques such as block, edge, back and final sanding
• K 18 sanding materials such as scratch pads, sandpaper and blend paste (blend prep)
• K 19 types of chip guard materials such as water-borne and acrylic
• K 20 uses of paintable and non-paintable chip guards
• K 21 appropriate drying timeframes for sanding
• K 22 limitations of chip guards
• K 23 types of seam sealers such as brushable, solid, two-part and self-levelling
• K 24 tooling methods for applying seam sealers
• K 25 types of additives such as flexible additives, accelerators, retarders and fish-eye eliminators

Sub-task - C-6.01 Mixes repair materials.

Key Competencies

• C-6.01.01 mix putty with appropriate amount of hardener on a non-porous mixing board, according to manufacturers’ recommendations
• C-6.01.02 measure and stir quantities of primers and primer surfacers as per job size, according to manufacturers’ recommendations
• C-6.01.03 shake aerosol type repair materials such as gravel guards and etch primers
• C-6.01.04 incorporate additives while mixing repair material, according to best practices and based on substrate and environmental conditions

Sub-task - C-6.02 Applies repair materials.

Key Competencies

• C-6.02.01 spread putty firmly and evenly over imperfections using tools such as putty knives and plastic spreaders according to industry standards
• C-6.02.02 use spray gun with appropriate nozzle assembly, and adjust pattern, fluid delivery and air pressure to apply primer and primer surfacers according to manufacturers’ recommendations
• C-6.02.03 use aerosol or gun to spray gravel guard onto repaired area to reproduce OEM texture and finish
• C-6.02.04 tool seam sealer onto repaired area to reproduce OEM texture and finish